The present invention relates to a call screening system which can be added on to and used in conjunction with a telephone system such as a PBX or Centrex telephone system.
Various types of call screening systems have been developed and utilized over the years for enabling calls directed to a particular user within the system to be screened prior to the user receiving the call. There is an increasing demand for personalized answering services and call screening operations so that a user having his calls screened will have the phone answered with his name. In developing improved call screening systems, provisions have been made for enabling the person doing the screening of the incoming calls to answer with the name of the user to which the call is directed; for example, a secretary screening calls can answer the incoming call with the announcement "Mr. Smith's office."
Various types of electronic telephone systems have built in limited call screening abilities. Various problems have been encountered, however, in adding call screening operations onto existing PBX and Centrex telephone systems. In order to add the call screening operation onto the PBX and Centrex telephone systems with provisions for the person doing the screening to answer an incoming call with some type of identification announcement for the particular phone being screened, it has been necessary to utilize two sets of tip/ring telephone lines for each telephone extension within the telephone system being screened. In such systems, a voice path is provided across a first tip/ring line to the screening telephone extension and a data path is provided over a second tip/ring line to such telephone extension. The second tip/ring line, i.e. the data line, provides a path over which an identification signal can be sent to the screening attendant for identifying the particular telephone extension actually being called by the incoming call on the voice tip/ring line. Consequently, with such a system two lines need to be provided for each screening telephone extension.
In an alternative type of call screening system, the answering attendant who initially receives the calls coming into the telephone system after ringing the screening telephone extension will stay on the telephone line and indicate the person that the call is actually for before connecting the incoming call to the screening telephone extension. The attendant at the screening telephone extension then can answer the call directed to such extension with an announcement indicating the particular telephone extension being called, e.g., "Mr. Smith's office." This type of system, however, slows down the productivity of the answering attendant answering the calls coming into the main telephone system since the attendant must remain on the line until the screening telephone extension is actually answered.
While various electronic telephone systems have been provided with the built in ability to eliminate the use of the extra telephone tip/ring line while still providing a call screening operation, such electronic telephones only enable a screening telephone extension to screen telephone calls for four to six telephone extension lines.